/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.runners.fnexecution.environment;



import com.bff.gaia.unified.model.pipeline.v1.RunnerApi.Environment;

import com.bff.gaia.unified.runners.fnexecution.control.InstructionRequestHandler;



import javax.annotation.concurrent.ThreadSafe;



/**

 * A {@link RemoteEnvironment} that wraps a running Docker container.

 *

 * <p>A {@link DockerContainerEnvironment} owns both the underlying docker container that it

 * communicates with an the {@link InstructionRequestHandler} that it uses to do so.

 */

@ThreadSafe

class DockerContainerEnvironment implements RemoteEnvironment {



  static DockerContainerEnvironment create(

      DockerCommand docker,

      Environment environment,

      String containerId,

      InstructionRequestHandler instructionHandler) {

    return new DockerContainerEnvironment(docker, environment, containerId, instructionHandler);

  }



  private final Object lock = new Object();

  private final DockerCommand docker;

  private final Environment environment;

  private final String containerId;

  private final InstructionRequestHandler instructionHandler;



  private boolean isClosed = false;



  private DockerContainerEnvironment(

      DockerCommand docker,

      Environment environment,

      String containerId,

      InstructionRequestHandler instructionHandler) {

    this.docker = docker;

    this.environment = environment;

    this.containerId = containerId;

    this.instructionHandler = instructionHandler;

  }



  @Override

  public Environment getEnvironment() {

    return environment;

  }



  @Override

  public InstructionRequestHandler getInstructionRequestHandler() {

    return instructionHandler;

  }



  /**

   * Closes this remote docker environment. The associated {@link InstructionRequestHandler} should

   * not be used after calling this.

   */

  @Override

  public void close() throws Exception {

    synchronized (lock) {

      // The running docker container and instruction handler should each only be terminated once.

      // Do nothing if we have already requested termination.

      if (!isClosed) {

        isClosed = true;

        instructionHandler.close();

        docker.killContainer(containerId);

      }

    }

  }

}